Patent Fr 9907034, directed toward a chest wall distractor, describes and claims a mechanical device that can monitor the growth of the bones in incorrect formation while correcting the deformities of the trunk without prohibiting or obstructing the patient's growth, but it is limited in its application to a deformity at the level of the thorax; it cannot be applied to a deformity involving the lumbar spine of the child since his or her growth could be impaired by placing the device directly on the vertebrae.
Patent Fr 109628000, entitled Flexible vertebral linking device consisting of elements that allow the overcoming of a spinal deformity, is largely a cushioning device comprised of rigid components holding visco-elastic means that can cushion the mechanical stresses in the preferred directions.
This device was designed to offset the stresses sustained by the vertebrae of the human body in a multi-axial fashion; it was not intended to be lengthened during displacements by stretching as is the case of the device described in the previous patent.